1918 Flu Pandemic. 100 Years. We Remember. We Prepare.Seasonal Flu vs. Pandemic FluInfluenza is one of the world\u2019s greatest infectious disease challenges. But did you know that seasonal flu and pandemic flu are not the same?What is seasonal flu?Influenza (flu) is a contagious respiratory illness caused by flu A and B viruses that infect the human respiratory tract. Annual flu epidemics occur among people worldwide.What is pandemic flu?A flu pandemic is a global outbreak of a new flu A virus in people that is very different from current and recently circulating seasonal flu A viruses.How often do seasonal flu epidemics occur?Epidemics of seasonal flu happen every year. Fall and winter is the time for flu in the United States.How often d...